1. Field of the Invention
The present invention relates to a method for timing a clock, and more particularly to a method having multiple equi-spaced references marked on the hour hand wheel so that a photoelectric element is able to sense these references for timing the hour hand, the minute hand and the second hand respectively in a short period of time.
2. Prior Art Description
A radio clock (R/C) can receive a signal sent from the time station for timing. The conventional ways of timing a clock include a power-on timing, a forcing timing and a periodic timing. The power-on timing is the function when the clock is initiated for the first time by power. The forcing timing is the function initiated by the user. The periodic timing is the function initiated automatically in a predetermined time interval.
With reference to FIG. 1, the current radio clock includes a receiving circuit 12 and a processor 13. The receiving circuit 12 receives a time signal sent from the time station via an antenna 11 and decodes the signal before sending it to the processor 13 for processing. The processor 13 is in charge of the operation of the entire timing. When the time function is initiated, the processor 13 will control the hour, the minute and the second hands back to zero (12 o""clock). Taking FIG. 2 for reference, the control of the hour, the minute and the second hands back to zero normally is completed by a photoelectric element 16. The timing function generally is operated by the photoelectric element 16 by judging a reference 17 marked on the hour hand wheel 18 (or the wheel of the minute hand or the wheel of the second hand). With the reference 17, the photoelectric element 16 is able to tell whether the hour, the minute and the second hands are at the right position. That is, if the photoelectric element 16 senses the reference 17 on the hour hand wheel 18, the hour hand is at the right position (at the numeral of 12 on the R/C).
As for the mechanical clock, the wheel of the second hand is driven by a rotor. Then, a first reduced gear is applied to the second hand to drive the wheel of the minute hand. A second reduced gear is used to drive the wheel of the hour hand. Thus, initiation of the timing function to the clock will take much time to set the hour, minute and the second hands back to zero (12 o""clock). In other words, when the photoelectric element 16 senses the reference 17 on the wheel 18 of the hour hand, the wheel of the second hand will revolve 660 times and the corresponding second hand will also revolve 660 times before the reference 17 is sensed. Because of that, the mechanical radio clock uses two sets of motors to drive the second hand and the minute hand respectively, as shown in FIG. 1. One set of the motor 14 drives the second hand and the other set of the motor 15 drives the minute hand so that the movement of the wheel of the second hand is independent to the wheels of the hour hand and the minute hand. Taking FIG. 2 for reference again, the minute hand wheel 19 drives the hour hand wheel 18 through the reduced gear (not shown). The reference 17 is marked on the hour hand wheel 18. When the photoelectric element 16 senses the reference 17, which means the corresponding hour and minute hands are back to their original positions (12 o""clock). As for the second hand, the same manner is used to see if the second hand is back to the zero position (12 o""clock). Suppose the timing function is initiated at one o""clock (01:00), one revolution of the second hand wheel will allow the photoelectric element 16 to sense the reference marked on the second hand wheel. However, when the reference 17 is sensed by the photoelectric element 16, the minute hand wheel 19 will revolve eleven (11) times. Although this method indeed saves a lot of time in timing when compared with the one described earlier, it still wastes much time.
The present invention provides an improved method for timing a radio clock to overcome the above mentioned shortcomings.
The primary objective of the invention is to provide an improved method for timing a clock by using multiple equi-spaced references marked on the hour hand wheel so that a photoelectric element is able to sense these references for timing the hour hand, the minute hand and the second hand respectively in a short period of time.
Other objects, advantages and novel features of the invention will become more apparent from the following detailed description when taken in conjunction with the accompanying drawings.